Adamantane has been found to be a useful building block in the synthesis of a broad range of organic compounds. For a general survey of the chemistry of adamantane and its higher homologs including diamantane and triamantane, see Adamantane, The Chemistry of Diamond Molecules, Raymond C. Fort, Marcel Dekker, N.Y., 1976. The following references provide a general overview of adamantane polymer chemistry.
U.S. Pat. No. 3,457,318 to Capaldi et al. teaches the preparations of polymers of alkenyl adamantanes and alkenyl adamantanes useful as coatings, electrical appliance housings, and transformer insulation. The process, yielding polymers bonded through the tetrahedral bridgehead carbons, comprises contacting an adamantyl halide in the presence of a suitable catalyst with a material selected from the group consisting of substituted allyl halides and olefins to produce adamantyl dihaloalkanes or adamantyl haloalkanes as an intermediate product. The intermediate product is then dehalogenated or dehydrohalogenated, respectively, to produce the alkenyl adamantane final product.
U.S. Pat. No. 3,560,578 to Schneider teaches the reaction of adamantane or alkyladamantanes with a C.sub.3 -C.sub.4 alkyl chloride or bromide using AlCl.sub.3 or AlBr.sub.3 as the catalyst. The reference describes polymerization through C.sub.3 -C.sub.4 linkages connecting bridgehead carbon atoms in the starting adamantane hydrocarbon; See column 3, lines 35-55, as well as the structural illustrations in columns 3-5.
U.S. Pat. No. 3,580,964 to Driscoll discloses polyesters containing hydrocarbyladamantane moieties as well as novel intermediate diesters and crosslinked polymers prepared therefrom. The hydrocarbyladamantane moieties are bonded through the tetrahedral bridgehead carbons; See column 2, lines 6-46 and the diesters illustrated in column 3, lines 55-75.
U.S. Pat. No. 3,639,362 to Dulling et al. discloses novel copolymers having low mold shrinkage properties which are prepared from adamantane acrylate and methacrylates. The adamantane molecule is bonded to the polymer chain through tetrahedral bridgehead carbon atoms.
U.S. Pat. No. 3,649,702 to Pincock et al. discloses a reactive derivative of adamantane, 1,3 dehydroadamantane. The reference shows bridgehead substituents including halogens and alkyls; See column 1, lines 45-64.
U.S. Pat. No. 3,748,359 to Thompson teaches the preparation of an alkyladamantane diamine from an alkyladamantane diacid. The diamine product is illustrated at column 1, lines 20-30, clearly showing bonding through the bridgehead carbons.
U.S. Pat. No. 3,832,332 to Thompson teaches a polyamide polymer prepared from an alkyladamantane diamine. As discussed and illustrated in the Thompson '332 patent at column 2, lines 41-53, the polymer comprises repeating units which include the backbone structure of adamantane. Note that the adamantane structure is bonded to the polymer chain through its bridgehead carbons.
U.S. Pat. No. 3,903,001 to Gates et al. teaches a limited-slip differential lubricant composition which may optionally include adamantane. See in particular the list of C.sub.13 -C.sub.29 naphthenes at column 4, line 1 et seq.
U.S. Pat. No. 3,966,624 to Duling et al. teaches a power transmission fluid containing a saturated adamantane compound. The adamantane compound consists of adamantane-like structures connected through ester linkages, ether linkages, carboxylic acids, hydroxyl or carbonyl groups; See the Abstract as well as column 1, line 49 through column 2, line 50.
U.S. Pat. No. 3,976,665 to Feinstein et al. discloses a dianhydride containing an adamantane group bonded through the bridgehead carbons.
U.S. Pat. No. 4,043,927 to Duling et al. teaches a tractive drive which may optionally contain an alkyladamantane or alkyladamantanol dimer of the C.sub.12 -C.sub.19 range containing from 1 to 3 alkyl groups of the C.sub.1 -C.sub.3 range, wherein the dimer contains two adamantane nuclei which are linked together through an alkylene radical derived from and having the same number of carbon atoms as an alkyl group of the starting adamantane material.
U.S. Pat. No. 4,082,723 to Mayer et al. discloses aza-adamantane compounds for stabilizing polymers to retard degradation by light and heat. The compounds have an adamantane backbone structure with at least one bridgehead carbon replaced by nitrogen. Specified bridgehead carbons may also be replaced by phosphorus, a phosphoryl or thiophosphoryl group, or a methine group optionally substituted by a phenyl or methyl group; See column 1, line 4 through column 2, line 16. While the Mayer et al. patent teaches replacement of a methylene carbon with nitrogen attached to a substituent group, the reference neither teaches nor suggests polymerizing monomers through octahedrally disposed atoms.
U.S. Pat. No. 4,142,036 to Feinstein et al. discloses adamantane compounds having 2 to 4 bridgehead positions substituted with phenylacyl moieties suitable for producing polymers useful for forming shaped objects such as film, fiber, and molded parts. The ester-substituted adamantanes are also suitable as plasticizers for polyvinylchloride and other polymers. The Feinstein et al. '036 patent notes that the four bridgehead carbons are equivalent to each other and are also more susceptible to attack than the secondary carbons. Accordingly, the adamantane component of the polymer taught in Feinstein et al. '036 bonds through the tetrahedrally disposed bridgehead carbons.
U.S. Pat. No. 4,168,260 to Weizer et al. teaches nitrogen-substituted triaza-adamantanyl ureas useful as stabilizers for thermoplastic materials. Nitrogen replaces carbon in three of the four bridgehead positions.
U.S. Pat. No. 4,332,964 to Bellmann et al. discloses diacrylate and dimethacrylate esters containing bridegehead substituted adamantane monomers. The polymer synthesis technique disclosed at column 3, line 62 through column 7, line 61 includes halogen addition at bridgehead carbons followed by replacement of the halogen with the selected link of the polymer chain.
The following references are representative of the art of lubricant-grade synthetic oligomers.
U.S. Pat. Nos. 3,676,521, 3,737,477, 3,851,011, and 3,923,919 to Stearns et al. teach lubricants having high Viscosity Index, low pour point, and high stability which comprise ethylene-propylene copolymers produced from monoolefin mixtures containing ethylene and propylene over catalysts including vanadium-aluminum or titanium-aluminum Ziegler-type catalyst systems.
U.S. Pat. No. 3,972,243 to Driscoll et al. discloses compositions including traction fluids, antiwear additives, as well as lubricant stocks containing a gem-structured hydrocarbon backbone, which compositions are produced by ozonolysis of polyolefins, particularly polyisobutylene oligomers.
U.S. Pat. No. 4,182,922 to Schick et al. teaches a synthetic hydrocarbon oil and a method of making the same involving the copolymerization of propylene or propylene plus higher 1-olefins with small amounts of ethylene.
U.S. Pat. No. 4,239,927 to Brennan et al. relates to a process for producing synthetic hydrocarbon oils by the polymerization of olefins using an aluminum halide catalyst. More specifically, the reference provides a method for preventing accumulation of certain organic halides which were found to be corrosive to process equipment by reacting such organic halides with aromatic hydrocarbons to evolve an alkylation product.
U.S. Pat. No. 4,463,201 to Schick et al. discloses a process for producing high quality synthetic lubricating oils by the copolymerization of ethylene, propylene, and a third 1-olefin, and subsequently dewaxed via a urea adduction process.
U.S. Pat. No. 4,520,221 to Chen teaches a process for producing high Viscosity Index lubricants from light olefins over a catalyst having the structure of ZSM-5, the surface acidity of which has been inactivated by treatment with a suitable base material.
U.S. Pat. No. 4,547,613 to Garwood et al. teaches the conversion of olefin-rich hydrocarbon streams such as ethylene and containing up to about 16 carbon atoms to high Viscosity Index lubricant base stocks by contacting the olefins with a catalyst having the structure of ZSM-5 under elevated pressure.
U.S. Pat. No. 4,912,272 to Wu relates to lubricant mixtures having unexpectedly high viscosity indices. More specifically, the lubricant mixtures comprise blends of high Viscosity Index polyalphaolefins prepared with activated chromium on silica, polyalphaolefins prepared with BF.sub.3, aluminum chloride, or Ziegler-type catalysts.
The preceding references elucidate several advantageous aspects of synthetic lubricant, including high Viscosity Index, as well as good lubricity and thermal stability. Thus it would be highly desirable to provide a relatively low molecular weight high viscosity synthetic lubricant blending stock for increasing the kinematic viscosity of blended synthetic lubricants.